Computer and method for reflecting path redundancy configuration of first computer system in second computer system

ABSTRACT

Mapping management information denoting the mapping of a first host and first host volume and a second host and second host volume is prepared beforehand. First-path-redundancy information, which is related to the redundancy of a first path of the first host volume, is acquired, and a second host volume and second host mapped to this first host volume and the first host thereof are specified by referencing the mapping management information. The redundancy of a second path, which links the specified second host volume and a second storage volume, is decided based on the first-path-redundancy information. Second-path-redundancy information, which is related to the decided second-path redundancy, is outputted to configure the decided second-path redundancy in the above-mentioned specified second host.

CROSS-REFERENCE TO PRIOR APPLICATION

This application relates to and claims the benefit of priority fromJapanese Patent Application number 2007-294925, filed on Nov. 13, 2007,the entire disclosure of which is incorporated herein by reference.

BACKGROUND

The present invention generally relates to the management of informationrelated to a computer system constituting one or more hosts and storagesystems.

The so-called remote copy technique by which data stored in a firststorage system is copied to a second storage system is known (JapanesePatent Laid-open No. 2006-301891, hereinafter referred to as PatentDocument 1). For example, even if a disaster or the like makes itimpossible to acquire data from the first storage system, a job can becontinued by using the data stored in the second storage system.

A first computer system can be constructed using the first storagesystem, and one or more first hosts connected thereto. The first hosthas a first host volume. The first host volume is a logical devicemapped to a first storage volume that the first host recognizes. Thefirst storage volume is a logical volume of the first storage system. Aplurality of first paths can be established between the first hostvolume and the first storage volume. The first host can managepluralities of first paths established between respective first hostvolumes and respective first storage volumes.

Similarly, a second computer system can be constructed using the secondstorage system, and one or more second hosts connected thereto. Thesecond host has a second host volume. The second host volume is alogical device mapped to a second storage volume that the second hostrecognizes. The second storage volume is a logical volume of the secondstorage system. A plurality of second paths can be established betweenthe second host volume and the second storage volume. The second hostcan manage pluralities of second paths established between respectivesecond host volumes and respective second storage volumes.

While carrying out operations using the first host, it is possible tologically connect and disconnect a desired path of the plurality offirst paths connected to the same first storage volume by switching thestate of the desired path back and forth between active and passive. Inother words, the redundancy of the first path can be configured for thefirst storage volume. The configuration of the redundancy of the firstpath is carried out manually.

When the base of operations switches from the first computer system tothe second computer system due to a disaster or the like, it isdesirable that the same redundancy as the redundancy of the first path,which was optimized in accordance with the operation of the firstcomputer system, be configured in the second computer system as well.

However, configuring path redundancy manually is extremely burdensome.For example, when the second computer system comprises anywhere fromseveral tens of units to several hundreds of units of the second hosts,the total number of paths to be configured can number several thousand,and configuring, for the respective second storage volumes, the samepath redundancy as the redundancy of the first path, which is connectedto the first storage volume that configures a volume pair, is anenormous burden.

SUMMARY

Therefore, an object of the present invention is to reflect the pathredundancy configured in the first computer system in the secondcomputer system without placing much of a burden on the individualsinvolved.

The other objects of the present invention should become clear from thefollowing explanations.

Mapping management information denoting the correspondence between afirst host and a first host volume, and a second host and a second hostvolume, is prepared beforehand. First-path-redundancy informationrelated to the redundancy of the first path for the first host volume isacquired, and the second host volume and second host mapped to thisfirst host volume and the first host thereof are specified byreferencing the mapping management information. The redundancy of thesecond path, which links the specified second host volume to the secondstorage system, is decided based on first-path-redundancy information.Second-path-redundancy information related to the redundancy of thedecided second path is outputted for configuring the redundancy of thedecided second path in the above-mentioned specified second host.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram showing an example of the overall constitution of asystem related to a first embodiment of the present invention;

FIG. 2 is a schematic diagram of paths established between a copy-sourcestorage system and a copy-source host;

FIG. 3A shows an example of the configuration of the copy-source host;

FIG. 3B shows an example of the configuration of a path status table;

FIG. 4A shows an example of the configuration of a copy-source storagesystem;

FIG. 4B shows an example of the configuration of a CHA/VOL table;

FIG. 4C shows an example of the configuration of a LUN security table;

FIG. 5A shows an example of the configuration of a copy-sourcemanagement computer;

FIG. 5B shows an example of the configuration of an integratedmanagement computer;

FIG. 6A shows an example of the configuration of a host volume mappingmanagement table;

FIG. 6B shows an example of the configuration of a path status mappingmanagement table;

FIG. 7 shows an example of the flow of processing carried out bycopy-source multi-path management software;

FIG. 8 shows an example of the flow of processing carried out byintegrated management software;

FIG. 9 shows an example of the flow of a copy-target redundancy decisionprocess;

FIG. 10 is a schematic diagram of a mode for deciding copy-targetredundancy;

FIG. 11 shows an example of the flow of processing carried out bycopy-target multi-path management software;

FIG. 12 shows an example of the flow of processing carried out bycopy-source storage management software;

FIG. 13 shows an example of the flow of processing carried out bycopy-target storage management software;

FIG. 14 shows the flow of copy-target redundancy information up until itreaches the copy-target host 105T in a second embodiment of the presentinvention;

FIG. 15 shows an example of the overall constitution of a system in athird embodiment of the present invention;

FIG. 16A shows an example of the configuration of a HBA port mappingmanagement table; and

FIG. 16B shows an example of the configuration of a CHA port mappingmanagement table.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

In Embodiment 1, the computer comprises a first-path-redundancyacquisition unit; a redundancy-configuration-destination specificationunit; a second-path-redundancy decision unit; and an output unit. Thefirst-path-redundancy acquisition unit acquires first-path-redundancyinformation. First-path-redundancy information is information related tothe redundancy of the first path, which links the first storage volumeof the first storage system to the first host volume of the first host.The redundancy-configuration-destination specification unit referencesthe host volume mapping management information (information denotingwhich first host volume of which first host is mapped to which secondhost volume of which second host), and specifies the second host volumemapped to the first host volume connected to the first path for whichredundancy has been configured. The second-path-redundancy decision unitdecides the redundancy of the second path, which links theabove-mentioned specified second host volume to the second storagevolume of the second storage system, based on the above-mentionedacquired first-path-redundancy information. The output unitsecond-path-redundancy information, which is information related to theredundancy of the above-mentioned decided second path, so that theabove-mentioned decided second-path redundancy is configured in thesecond host having the above-mentioned specified second host volume.

The first-path redundancy is a value based on the number of active firstpaths, which are the active-state first paths of the plurality of firstpaths which connect to the same first host volume and the same firststorage volume. The first-path-redundancy information, for example, canbe information on how many active first paths have been added ordropped.

The second-path redundancy is a value based on the number of activesecond paths, which are the active-state second paths of the pluralityof second paths, which connect to the same second host volume and thesame second storage volume.

The above-mentioned first storage system and one or more first hostsconstitute a first computer system. The above-mentioned first storagevolume is a logical volume in the above-mentioned first storage system.The above-mentioned first host volume is a logical device mapped to theabove-mentioned first storage volume recognized by the above-mentionedfirst host.

The above-mentioned second storage system and one or more second hostsconstitute a second computer system. The above-mentioned second storagevolume is a logical volume, which is in the above-mentioned secondstorage system, and which stores data that is stored in theabove-mentioned first storage volume. The above-mentioned second hostvolume is a logical device mapped to the above-mentioned second storagevolume recognized by the above-mentioned second host.

In Embodiment 2 according to Embodiment 1, when the number of firstpaths for which redundancy has been configured and the number of secondpaths mapped to the redundancy-configured first paths are the same, theabove-mentioned second-path-redundancy decision unit decides aredundancy for the above-mentioned mapped second path that is the sameredundancy as the first-path redundancy.

In Embodiment 3 according to either Embodiment 1 or 2, when the numberof first paths for which redundancy has been configured P_(s) and thenumber of second paths mapped to the redundancy-configured first pathsP_(t) are different, the above-mentioned second-path-redundancy decisionunit decides the redundancy for the above-mentioned mapped second pathsuch that the percentage of the number of active second paths for theabove-mentioned P_(t) is as close as possible to the percentage of thenumber of active first paths for the above-mentioned P_(s).

In Embodiment 4 according to either Embodiment 1 or 2, when the numberof first paths for which redundancy has been configured P_(s) and thenumber of second paths mapped to the redundancy-configured first pathsP_(t) are different, the above-mentioned second-path-redundancy decisionunit decides the redundancy of the above-mentioned mapped second pathbased on the configured redundancy of the number of either active orpassive first paths.

In Embodiment 5 according to any of Embodiments 1 through 4, whenP_(s)<P_(t) due to an error having occurred in any of the first paths,the above-mentioned second-path-redundancy decision unit decides theredundancy of the above-mentioned mapped second path such that thenumber of second paths in the passive state equals the number of failedfirst paths, which are first paths in which errors have occurred.

In Embodiment 6 according to any of Embodiments 1 through 5, whenP_(s)>P_(t) due to an error having occurred in any of the second paths,the above-mentioned second-path-redundancy decision unit decides theredundancy of the above-mentioned mapped second path such that thenumber of passive second paths, which are second paths in the passivestate, is as close as possible to the number of passive first paths,which are first paths in the passive state, by allocating an activefirst path for an error second path, which is a second path in which anerror has occurred.

In Embodiment 7 according to any of Embodiments 1 through 6, theabove-mentioned output unit writes the above-mentionedsecond-path-redundancy information to the first storage volume mapped tothe first host volume to which the redundancy-configured first paths areconnected.

In Embodiment 8 according to any of Embodiments 1 through 7, theabove-mentioned first storage system has a plurality of first storageports and a first access controller. The above-mentioned first storageport is a communication port for receiving an access command from thefirst host. The above-mentioned first access controller is a firststorage port to which has been mapped a first identification informationmapped to a first host port, which is either the first host or acommunication port thereof, and when an access command is received, theabove-mentioned first access controller allows access to this accesscommand if this access command is from either the first host or thefirst host port that is mapped to the above-mentioned firstidentification information. The above-mentioned second storage systemhas a plurality of second storage ports, and a second access controller.The above mentioned second storage port is a communication port forreceiving an access command from the second host. The above-mentionedsecond access controller is a second storage port to which has beenmapped a second identification information mapped to a second host port,which is either the second host or a communication port thereof, andwhen an access command is received, the above-mentioned second accesscontroller allows access to this access command if this access commandis from either the second host or the second host port that is mapped tothe above-mentioned second identification information. Theabove-mentioned computer comprises a first-security-informationacquisition unit; an identification information/storage portspecification unit; and a second-security-information output unit. Thefirst-security-information acquisition unit acquires first securityinformation, which is information related to what first identificationinformation is mapped to which first storage port. The identificationinformation/storage port specification unit references identificationmapping management information, which is information denoting whichfirst identification information is mapped to which secondidentification information, and storage port mapping managementinformation, which is information denoting which first storage port ismapped to which second storage port, and specifies the secondidentification information mapped to the first identificationinformation specified from the above-mentioned first securityinformation, and the second storage port mapped to the first storageport specified from the above-mentioned first security information. Thesecond-security-information output unit outputs second securityinformation, which is information related to the specified secondstorage port and the specified second identification information, suchthat the above-mentioned specified second identification information ismapped to the above-mentioned specified second storage port.

In Embodiment 9 according to Embodiment 8, the above-mentioned firstsecurity information is information related to which firstidentification information mapped to which first storage port willchange to what first identification information. The above-mentionedidentification information/storage port specification unit specifies thepre-change second identification information mapped to the pre-changefirst identification information specified from the above-mentionedfirst security information, and the post-change second identificationinformation mapped to the post-change first identification informationspecified from the above-mentioned first security information. Theabove-mentioned second security information comprises the specifiedpre-change second identification information and post-change secondidentification information.

In Embodiment 10 according to either of Embodiments 8 or 9, theabove-mentioned acquired first-path-redundancy information isinformation related to the post-change redundancy of the first paththrough the first storage port, which was changed as a result of thefirst identification information being mapped to the first storage port.

At least one of the above-described first-path-redundancy acquisitionunit, redundancy-configuration-destination specification unit,second-path-redundancy decision unit, output unit,first-security-information acquisition unit, identificationinformation/storage port specification unit, orsecond-security-information output unit can be constructed using eitherhardware, a computer program or a combination thereof (for example, onepart can be realized via a computer program, and the remainder can berealized via hardware). The computer program is executed by being readinto a prescribed processor. Further, a storage region that resides in ahardware resource, such as a memory, can be used as needed wheninformation processing is carried out by reading the computer programinto the processor. Further, the computer program can be installed inthe computer from a CD-ROM or other such recording medium, or downloadedto the computer via a communication network.

An embodiment of the present invention will be explained in detail belowwhile referring to the figures. To make the explanation easier tounderstand at this time, computer program may be used as the subjectinstead of CPU when explaining a process carried out by the CPU readingin and executing the computer program.

FIG. 1 is a diagram showing an example of the overall constitution of asystem related to the first embodiment of the present invention.

There is a copy-source computer system 111S and a copy-target computersystem 111T. The copy-source computer system 111S is the systemconstituting the data copy source, for example, the system currently inuse. Conversely, the copy-target computer system 111T is the systemconstituting the data copy target, for example, the system that isstanding by. When the copy-source computer system 111S goes down as theresult of a disaster or the like, the copy-target computer system 111Tswitches from the standby system to the current-use system, andoperation continues. Furthermore, the copy-target computer system 111Tcan also be the current-use system.

In FIG. 1, the symbol “S” is appended at the end of the referencenumerals of the components residing in the copy-source computer system111S. Conversely, the symbol “T” is appended at the end of the referencenumerals of the components residing in the copy-target computer system111T. For example, in copy-source computer system 111S, for example, acopy-source storage system 101S and one or more copy-source hosts 105Sare connected to an FC (Fibre Channel) network configured by one or moreFC switches 103S, and the copy-source storage system 101S, FC switch103S, copy-source host 105S, and a copy-source management computer 107Sare connected to a IP (Internet Protocol) network 109S. Similarly, inthe copy-target computer system 111T, for example, a copy-target storagesystem 101T and one or more copy-target hosts 105T are connected via anFC cable, for example, to an FC (Fibre Channel) network configured fromone or more FC switches 103T, and the copy-target storage system 101T,FC switch 103T, copy-target host 105T, and a copy-target managementcomputer 107T are connected to a IP (Internet Protocol) network 109T.

The copy-source storage system 101S is the storage system that becomesthe data copy source in a remote copy, and the copy-target storagesystem 101T is the storage system that becomes the data copy target in aremote copy. These storage systems 101S & 101T are connected by a leasedline (for example, a FC (Fibre Channel) cable) 117. Data transceived atthe time of a remote copy goes by way of the leased line 117. A dataremote copy can also be carried out from the copy-source storage system101S to the copy-target storage system 101T by way of an FC network orother such communication network instead of the leased line 117.Further, at least one of the copy-source storage system 101S orcopy-target storage system 101T can be a plurality of storage systems.

There is an IP network 115 to which the IP network 109S inside thecopy-source computer system 111S and the IP network 109T inside thecopy-target computer system 111T are connected, and an integratedmanagement computer 113 is connected to this IP network 115. Theintegrated management computer 113 can be connected so-calledout-of-band like this, or can be connected so-called in-band (Forexample, the integrated management computer 113 can also be connected tothe FC switch 103S and FC switch 103T).

The respective configurations of the copy-source computer system 111Sand the copy-target computer system 111T are substantially the same.Hereinafter, the copy-source computer system 111S will be taken as arepresentative example, and the paths established between the host andstorage system, and the respective components of the computer systemwill be explained.

FIG. 2 is a schematic diagram of paths established between copy-sourcestorage system 101S and copy-source host 105S.

The copy-source storage system 101S has a copy-source storage volume143S, and the copy-source host 105S has a copy-source host volume 133S.The copy-source host volume 133S is a logical device (for example, adevice file), which is mapped to the copy-source storage volume 143Srecognized by the copy-source host 105S. A “recognized copy-sourcestorage volume 143S”, for example, is a logical volume mapped to replyinformation in response to an inquiry command or other such prescribedquery command.

The copy-source storage system 101S has a plurality of CHA ports 141S,and the copy-source host 105S has one or a plurality of HBA ports 131S.The CHA port 141S is the communication port of a channel adapter (CHA),which will be explained hereinbelow. The HBA port 131S is thecommunication port of the host bus adapter (HBA) comprised in thecopy-source host 105S. The respective CHA ports 141S and respective HBAports 131S are physically connected (for example, via cable) to therespective communication ports (switching ports) 121S of the FC switch103S. A WWN (World Wide Name), which is a unique identifier of acommunication port, is configured in each CHA port 141S and HBA port131S.

A plurality of paths are established between the copy-source host volume133S and the copy-source storage volume 143S. Hereinafter, a pathexisting in the copy-source computer system 111S may be called a“copy-source path”, and similarly, a path existing in the copy-targetcomputer system 111T may be called a “copy-target path”. Further, theredundancy of the copy-source path may be called the “copy-sourceredundancy”, and the redundancy of the copy-target path may be calledthe “copy-target redundancy”. Incidentally, what is referred to as a“path” in this embodiment is not a physical path, such as a cable thatlinks communication ports, but rather a logical path configured by aplurality of information elements, such as the identifier of a storagevolume (for example, a LUN (Logical Unit Number)) and the identifier ofa CHA port (for example, a port number).

According to the four dotted lines shown in FIG. 2, four copy-sourcepaths are established between one copy-source storage volume 143S andone copy-source host volume 133S. The black circles on the respectivedotted lines show the information elements configuring the paths. Morespecifically, as path-configuring information elements, there are acopy-source host volume identifier (for example, “HV01”), an HBA port131S identifier (for example, “HP01”), a CHA port 141S identifier (forexample, “SP01”), and a copy-source storage volume identifier (forexample, “SV01”). Hereinafter, at least one of the copy-source hostvolume, HBA port, CHA port or copy-source storage volume may be shownusing the identifier rather than the reference numeral.

The redundancy of the copy-source path linking the copy-source hostvolume HV01 and the copy-source storage volume SV01 is not determinedbased on the number of copy-source paths (for example, four), but ratheris determined on the basis of which of these plurality of copy-sourcepaths is online (active) and which is offline (passive). Morespecifically, for example, the more active copy-source paths there areamong the plurality of copy-source paths, the higher the copy-sourceredundancy, and conversely, the fewer the active copy-source paths, thelower the copy-source redundancy. In this embodiment, the configuredcopy-source redundancy is reflected (for example, copied) in the secondcomputer system 111. This reflection can be carried out regularly, orcan be done when the copy-source redundancy changes. In other words, thecopy-source redundancy can be reflected in the copy-target computersystem 111T either synchronously or asynchronously when this copy-sourceredundancy changes. Furthermore, when the copy-source redundancy isreflected in the copy-target computer system 111T, copy-targetredundancy information denoting the decided copy-target redundancy issent so that the copy-target redundancy, which is decided on the basisof the copy-source redundancy, is configured in the copy-target hostmapped to the copy-source host. The transmission destination of thecopy-target redundancy information is the copy-target host 105T in thisembodiment. However, the present invention is not limited to this, andthe transmission destination of the copy-target redundancy informationcan also be the copy-source storage volume 143S (or the copy-targetstorage volume 143T), as will be explained in the second embodimentdescribed hereinbelow.

When the copy-source host volume HV01 in the copy-source host 105S isspecified from the below-described operations software as the I/Odestination, an I/O command specifying the copy-source storage volumeSV01 mapped to the copy-source host volume HV01 is sent from thecopy-source host 105S. At this time, the I/O command goes by way of anonline copy-source path selected by the below-described copy-sourcemulti-path management software from the plurality of online copy-sourcepaths connected to the copy-source host volume HV01.

For example, at least one of the following two reasons can be given asthe purpose for making a path redundant.

(1) Path error avoidance: When an error occurs in any path due to thephysical disconnection of a FC cable or the like, operation can continuebecause the desired storage volume can be accessed using another activecopy-source path.

(2) Load balancing: A CHA port and FC cable are ordinarily used by aplurality of hosts. For this reason, the load on a certain CHA port orFC cable intensifies in line with an increase in traffic, and canpotentially lead to a drop in access performance to the storage volume.Making a path redundant can balance the load to the CHA port or FCcable, making it possible to avoid performance degradation.

Copy-source redundancy, for example, is decided in accordance with atleast one of the performance, frequency of use, and importance of theoperation of the below-described operations software executed by thecopy-source host 105S. The administrator of the copy-source host 105Sand/or copy-source storage system 101S optimizes copy-source redundancyto meet safety and performance requirements. This optimization is notsomething that is only implemented one time when the copy-source host105S and/or copy-source storage system 101S are installed, but rather,for example, must be changed frequently in accordance with daily changesin operation (for example, at least one of characteristic feature,frequency of use, and importance).

The redundancy of the copy-source path changes in accordance with theoperation of the below-described copy-source multi-path managementsoftware installed in the copy-source host 105S. If a desiredcopy-source path is offline, this copy-source path constitutes alogically disconnected state, and if the desired copy-source path isonline, this copy-source path constitutes a logically connected state.

Further, the logical connection of the copy-source path can becontrolled by LUN security information and FC switch zoning, which willbe described below.

Zoning is a type of security function. More specifically, for example, azoning table 171S is stored in a FC switch 103S storage resource (forexample, a memory). A combination of viable ports (for example, a setcomprising the identifier of the HBA port 131S and the identifier of theCHA port 141S) can be configured in the zoning table 171S for eachswitching port 121S of the FC switch 103S. Based on this zoning table171S, control is exercised to determine whether or not a commandreceived from the HBA port 131S of the copy-source host 105S istransferred to the CHA port 141S of the copy-source storage system 101S.

FIG. 3A shows an example of the configuration of the copy-source host105S.

The copy-source host 105S is the computer for accessing the copy-sourcestorage volume 143S comprised in the copy-source storage system 101S.The copy-source host 105S, for example, comprises a CPU 201S, memory203S, HBA (Host Bus Adapter) 211S, which has the HBA port 131S, and aport 135S that is connected to the IP network. The memory 203S, forexample, stores, as computer programs to be executed by the CPU 201S, anapplication program, such as operations software 205S for executing aprescribed operation, and multi-path management software (hereinafter,copy-source multi-path management software) 207S for managing therespective pluralities of copy-source paths connected to respectivecopy-source host volumes.

When the copy-source host volume HV01 is specified as the I/Odestination by the operations software 205S, the copy-source multi-pathmanagement software 207S selects one online copy-source path from amongthe plurality of online copy-source paths connected to the copy-sourcehost volume HV01 in accordance with either random or prescribed rules(for example, a load balancing algorithm). An I/O command, whichspecifies the copy-source storage volume SV01 mapped to the specifiedcopy-source host volume HV01 , is sent via the selected copy-sourcepath.

In addition to information denoting what configuration of copy-sourcepaths are connected to which copy-source host volumes, the copy-sourcemulti-path management software 207S also manages the path status table209S for managing the states of the respective copy-source paths. Acopy-source host volume identifier, the number of online copy-sourcepaths, and the number of offline copy-source paths are recorded in thepath status table 209S for each copy-source host volume.

FIG. 4A shows an example of the configuration of the copy-source storagesystem 101S.

The copy-source storage system 101S, for example, can be configured as aRAID (Redundant Arrays of Independent (or Inexpensive) Disks) systemcomprising a large number of physical storage devices (for example, HDD)227S arranged in an array. As a controller, for example, the copy-sourcestorage system 101S comprises a CHA (Channel Adapter) 221S, DKA (DiskAdapter) 226S, switch 223S, shared memory 224S, and cache memory 225S.The controller of the copy-source storage system 101S controls access tothe physical storage devices 227S. Furthermore, for example, thefunctions of the copy-source storage system 101S controller can also bemounted in the FC (Fibre Channel) switch 103S, and the copy-sourcestorage system 101S can be realized by combining the FC switch 103S witha plurality of physical storage devices 227S.

The CHA 221S has one or a plurality of communication ports (CHA port)141S, which is communicably connected to an external device (forexample, the copy-source host 105S), and is for carrying out datacommunications with the external device. The CHA 221S is configured as amicrocomputer system (for example, a circuit board), which comprises aCPU 222S and a memory. The CHA 221S, for example, upon receiving a writecommand from the copy-source host 105S, writes the write-targeted datato the cache memory 225S. Further, upon receiving a read command fromthe copy-source host 105S, the CHA 221S sends to the copy-source host105S read-targeted data, which the DKA 226S has read out from thephysical storage device 227S and written to the cache memory 225S.

The DKA 226S has one or a plurality of communication ports, which iscommunicably connected to the respective physical storage devices 227S,and is for carrying out data communications with the physical storagedevices 227S. The DKA 226S is configured as a microcomputer system (forexample, a circuit board), which comprises a CPU and a memory. The DKA226S, for example, writes write-targeted data, which has been written tothe cache memory 225S from the CHA 221S, to the physical storage device227S, and writes read-targeted data read out from the physical storagedevice 227S to the cache memory 225S.

The switch 223S, for example, is a crossbar switch, and is a device,which interconnects the CHA 221S, DKA 226S, shared memory 224S, andcache memory 225S. Instead of the switch 223S, a bus or other such typeof connector can also be used.

The shared memory 224S, for example, can be configured from either anonvolatile or volatile semiconductor memory. The shared memory 224S,for example, stores control information used to control the copy-sourcestorage system 101S. As control information, for example, there aCHA/VOL table 231S and a LUN security table 233S. The CHA/VOL table231S, as shown in FIG. 4B for example, is a table denoting which CHA221S can access which copy-source storage volume 143S. The LUN securitytable 233S, as shown in FIG. 4C for example, is a table denoting whatLUN security information has been mapped to which CHA port 141S (whichport identifier) of which CHA 221S (which CHA identifier). As used here,LUN security information is information denoting the HBA port 131S withthe type of identification information (for example, a WWN) that isallowed access.

The cache memory 225S, for example, can be configured from a volatilesemiconductor memory. The cache memory 225S stores write-targeted datareceived from the copy-source host 105S, and read-targeted data read outfrom the physical storage device 227S. Furthermore, the shared memory224S and cache memory 225S can be configured as respectively individualmemories as in this embodiment, or can be configured as a single memory.

In the copy-source storage system 101S, for example, a RAID group 229Sis configured from a plurality of physical devices 227S. The RAID group229S, for example, provides a redundant storage mode based on RAID 1 orRAID 5. The copy-source storage volume 143S is created by allocating oneportion each of the respective storage areas of the plurality ofphysical storage devices 227S comprised in the RAID group 229S. Thecopy-source storage volume 143S is provided to the copy-source host 105Sfrom the copy-source storage system 101S.

FIG. 5A shows an example of the configuration of the copy-sourcemanagement computer 107S.

The copy-source management computer 107S is a computer for managing thecopy-source storage system 101S. The copy-source management computer107S, for example, comprises a CPU 301S, memory 315S, and port 317Sconnected to the IP network. The memory 315S, for example, stores as acomputer program to be executed by the CPU 301S copy-source storagemanagement software 303S for managing the copy-source storage system101S. The copy-source storage management software 303S manages a CHA/VOLconfiguration table 311S and a LUN security configuration table 313S.The configurations of the CHA/VOL configuration table 311S and LUNsecurity configuration table 313S are substantially the same as theconfigurations of the CHA/VOL table 231S shown in FIG. 4B and LUNsecurity table 233S shown in FIG. 4C.

FIG. 5B shows an example of the configuration of the integratedmanagement computer 113.

The integrated management computer 113 is for managing volumereplication in accordance with a remote copy between the copy-sourcestorage system 101S and the copy-target storage system 101T. Theintegrated management computer 113, for example, can configure theremote copy type for a storage volume pair as either synchronous orasynchronous, and can configure the storage volume pair. Further, theintegrated management computer 113 can also reflect the copy-sourceredundancy in the copy-target computer system 111T.

The integrated management computer 113, for example, comprises a CPU401, memory 407, and a port 409 connected to an IP network. The memory407, for example, stores, as a computer program executed by the CPU 401,integrated management software 403 for carrying out the reflection ofcopy-source redundancy in the copy target and so forth.

The integrated management software 403 manages a mapping managementtable 411, failure information table 413, path status management table415, LUN security management table 417, and CHA/VOL management table419. The configurations of the CHA/VOL management table 419 and LUNsecurity management table 417 are substantially the same as those of theCHA/VOL table 231S shown in FIG. 4B, and the LUN security table 233Sshown in FIG. 4C. As the mapping management table 411, for example,there is the host volume mapping management table 411A shown in FIG. 6A,the HBA port mapping management table 411B shown in FIG. 16A, and theCHA port mapping management table 411C shown in FIG. 16B. Normally, thecopy-source host volume 133S and copy-target host volume, which arerespectively mapped to the copy-source storage volume 143S and thecopy-target storage volume 143T configuring volume pairs, are mapped toone another.

As shown in FIG. 6A, the host volume mapping management table 411A isfor managing which copy-source host volume 133S is mapped to whichcopy-target host volume; the number of copy-source paths connected tothe copy-source host volume 133S; and the number of copy-target pathsconnected to the copy-target host volume. More specifically, forexample, the host volume mapping management table 411A records for eachcopy-source host volume 133S an identifier for the copy-source hostvolume 133S (for example, a number); the number of copy-source pathsconnected to this copy-source host volume 133S (the total of the numberof online copy-source paths and offline copy-source paths); theidentifier of the copy-source host 105S having this copy-source hostvolume 133S; the identifier (for example, a number) of the copy-targethost volume mapped to this copy-source host volume 133S; the number ofcopy-target paths connected to this copy-target host volume (the totalof the number of online copy-target paths and offline copy-targetpaths); and the identifier of the copy-target host 105T having thiscopy-target host volume. Furthermore, in the copy-source computer system111S and copy-target computer system 111T, the number of hosts and/orhost volumes can differ. In this case, the hosts and/or host volumeselected in accordance with arbitrary criteria by the user and/oradministrator as being highly important are made the copy-source host,copy-source host volume, copy-target host, and copy-target host volume(that is, the information related to these hosts and/or host volumes isrecorded in the host volume mapping management table 411A).

As shown in FIG. 16A, the HBA port mapping management table 411B is formanaging which HBA port in the copy source (hereinafter, copy-source HBAport) is mapped to which HBA port in the copy target (hereinafter,copy-target HBA port). More specifically, for example, the HBA portmapping management table 411B records for each copy-source HBA port theidentifier (for example, a number and/or WWN) of the copy-source HBAport; the identifier of the copy-source host 105S having thiscopy-source HBA port; the identifier (for example, a number and/or WWN)of the copy-target HBA port mapped to this copy-source HBA port; and theidentifier of the copy-target host 105T having this copy-target HBAport.

As shown in FIG. 16B, the CHA port mapping management table 411C is formanaging which CHA port in the copy source (hereinafter, copy-source CHAport) is mapped to which CHA port in the copy target (hereinafter,copy-target CHA port). More specifically, for example, the CHA portmapping management table 411C records for each copy-source CHA port theidentifier (for example, a number and/or WWN) of the copy-source CHAport; the identifier of the copy-source storage system 101S having thiscopy-source CHA port; the identifier (for example, a number and/or WWN)of the copy-target CHA mapped to this copy-source CHA port; and theidentifier of the copy-target storage system 101T having thiscopy-target CHA port.

The preceding is an explanation of the mapping management tables 411.

The failure information table 413 records information denoting thepresence or absence of a failure in the copy-source computer system101S.

The path status management table 415 is for managing the number ofonline paths and the number of offline paths for the respectivecopy-source host volumes and the respective copy-target host volumes.More specifically, for example, as shown in FIG. 6B, the path statusmanagement table 415 records for each copy-source host volume 133S theidentifier (for example, a number) of the copy-source host volume 133S;the number of online copy-source paths (copy-source-ON number) connectedto this copy-source host volume 133S; the number of offline copy-sourcepaths (copy-source-OFF number) connected to this copy-source host volume133S; the identifier of the copy-source host 105S having thiscopy-source host volume 133S; the identifier (for example, a number) ofthe copy-target host volume mapped to this copy-source host volume 133S;the identifier of the copy-target host 105T having this copy-target hostvolume; the number of online copy-target paths (copy-target-ON number)connected to this copy-target host volume; and the number of offlinecopy-target paths (copy-target-OFF number) connected to this copy-targethost volume.

The processing carried out by this embodiment will be explained below.

FIG. 7 shows an example of the flow of processing carried out by thecopy-source multi-path management software 207S.

The copy-source multi-path management software 207S waits for a changein the status of a copy-source path to be specified by the user (S101).

The copy-source multi-path management software 207S, upon receiving acopy-source path and a change to the status thereof from the user(S102), changes the status recorded in the path status table 209S mappedto the specified copy-source path (S103). That is, the path status table209S is updated. Furthermore, “change the status” in this embodimentsignifies that, if the pre-change status is online, the copy-source pathis changed to offline, and if the pre-change status is offline, thecopy-source path is changed to online. Thus, changing the status of thecopy-source path results in the copy-source redundancy for thecopy-source host volume 133S, to which the status-changed copy-sourcepath is connected, being changed as well.

Subsequent to S103, the copy-source multi-path management software 207Ssends the information in the record (row) in which the post-changestatus is recorded in the post-update path status table 209S to theintegrated management computer 113 (S104). Hereinafter, this sentinformation will be referred to as the “copy-source redundancyinformation”. The copy-source redundancy information, for example,comprises the copy-source host volume identifier; the number of onlinecopy-source paths (ON-number); and the number of offline copy-sourcepaths (OFF-number).

If the copy-source multi-path management software 207S detects a failurein the copy source (for example, a failure in the copy-source storagesystem 101S) (S105: YES), the copy-source multi-path management software207S notifies the integrated management computer 113 of the occurrenceof the failure (S106). Upon receiving this notification, the integratedmanagement computer 113 writes information denoting that a failure hasoccurred in the failure information table 413.

FIG. 8 shows an example of the flow of processing carried out by theintegrated management software 403.

The integrated management software 403, upon receiving the copy-sourceredundancy information from the copy-source multi-path managementsoftware 207S of a certain copy-source host 105S (S111: YES), updatesthe path status management table 415 (S112). More specifically, theintegrated management software 403 updates the ON-number and OFF-numberin the path status management table 415 mapped to the copy-source hostvolume identifier comprised in the received copy-source redundancyinformation to the ON-number and OFF-number comprised in the receivedcopy-source redundancy information.

Thereafter, the integrated management software 403 executes the process(hereinafter, the copy-target redundancy decision process) for decidingthe copy-target redundancy of the copy-target host volume mapped to thecopy-source host volume 133 s for which the copy-source redundancychanged.

The integrated management software 403, upon receiving a copy-targetredundancy reply request from the copy-target multi-path managementsoftware 207S of a certain copy-target host 105T (S113: YES), acquiresthe copy-target redundancy information mapped to this copy-target host105T from the path status management table 415, and sends the acquiredcopy-target redundancy information to this copy-target host 105T (S114).

The integrated management software 403, upon receiving a CHA/VOLconfiguration table 311S and/or LUN security configuration table 313Sfrom the copy-source storage management software 303S in the copy-sourcemanagement computer 107S (S115: YES), writes the information recorded inthe received tables 311S and/or 313S to the LUN security managementtable 417 and/or CHA/VOL management table 419 (S116). In S116, theintegrated management software 403 carries out a copy-target LUNsecurity change process as required. A case in which a copy-target LUNsecurity change process becomes necessary, and the copy-target LUNsecurity change process will be explained hereinbelow.

The integrated management software 403, upon receiving a table replyrequest from the copy-target storage management software in thecopy-target management computer 107T (S117: YES), acquires informationrelated to the copy target recorded in the LUN security management table417 and/or CHA/VOL management table 419, and sends the acquiredinformation to the copy-target management computer 107T (S118).Furthermore, the “information related to the copy target” referred tohere, in terms of the LUN security management table 417, is theidentifier of the CHA in the copy-target computer system 111T, theidentifier of the CHA port, and the LUN security information, and interms of the CHA/VOL management table 419, is the identifier of the CHAin the copy-target computer system 111T, and the identifier of thecopy-target storage volume.

FIG. 9 shows an example of the flow of copy-target redundancy decisionprocessing.

The integrated management software 403 references the host volumemapping management table 411A, specifies the number of copy-source paths(hereinafter, copy-source-path number) connected to the copy-source hostvolume 133S for which the copy-source redundancy has changed, and thenumber of copy-target paths (hereinafter, copy-target-path number)connected to the copy-target host volume mapped to this copy-source hostvolume 133S, and compares the specified copy-source-path number andcopy-target-path number (S121).

If the result of the comparison in S121 is that the copy-source-pathnumber and copy-target-path number are the same (S121: YES), theintegrated management software 403 decides the copy-target redundancy tobe the same redundancy as the post-change copy-source redundancy (S122).That is, the copy-target-ON number denoted by the decided copy-targetredundancy is the same as the copy-source-ON number denoted by thepost-change copy-source redundancy, and therefore the copy-target-OFFnumber denoted by the decided copy-target redundancy is the same as thecopy-source-OFF number denoted by the post-change copy-sourceredundancy.

Conversely, if the result of the comparison of S121 is that thecopy-source-path number and copy-target-path number are different (S121:NO), the integrated management software 403 decides the copy-targetredundancy based on either the ON-ratio according to the post-changecopy-source redundancy, or the post-change copy-source-ON number and/orcopy-target-ON number (S123). Furthermore, the ON-ratio is thepercentage of the ON-number relative to the number of paths, and, forexample, the ON-ratio according to the post-change copy-sourceredundancy is the percentage of the copy-source-ON number relative tothe copy-source-path number. Hereinafter, the ON-ratio according to thepost-change copy-source redundancy may be referred to as the“copy-source-ON ratio”, and the ON-ratio in the copy target may bereferred to as the “copy-target-ON ratio”. Further, the ON-ratio may beexpressed as a fraction. The numerator in these cases is the ON-number,and the denominator is the number of paths.

Subsequent to either S122 or S123, the integrated management software403 writes the copy-target-ON number and copy-target-OFF numberaccording to the decided copy-target redundancy in the path statusmanagement table 415 (S124).

The preceding is an explanation of the processing carried out by theintegrated management software 403. Furthermore, if, for example, theintegrated management software 403 receives the copy-source redundancyinformation and updates the path status management table 415, theintegrated management software 403 can carry out a copy-targetredundancy decision process, and can dynamically (actively) send thecopy-target redundancy information denoting the decided copy-targetredundancy to the copy-target host 105T without receiving copy-targetredundancy reply request from the copy-target host 105T. The copy-targethost 105T that becomes the transmission-destination here is thecopy-target host having the copy-target host volume specified from thesent copy-target redundancy information. Similarly, if, for example, theintegrated management software 403 receives the CHA/VOL configurationtable 311S and/or the LUN security configuration table 313S, and updatesthe LUN security management table 417 and/or the CHA/VOL managementtable 419, the integrated management software 403 can dynamically(actively) send the information related to the copy target recorded inthe LUN security management table 417 and/or CHA/VOL management table419 to the copy-target management computer 107T without receiving atable reply request from the copy-target management computer 107T.

However, there are two modes A and B for deciding the copy-targetredundancy in the above-described S123, for example, as shown in FIG.10. FIG. 10 (Aa) and (Ba) is a case in which the copy-target-path numberis larger than the copy-source-path number, and FIG. 10 (Ab) and (Bb) isa case in which the copy-target-path number is smaller than thecopy-source-path number. Further, in FIG. 10, the paths marked with an Xindicate the occurrence of errors, and these paths are not counted inthe copy-source-path number or the copy-target-path number.

Mode A is based on the post-change copy-source-ON number and/orcopy-target-ON number, and more specifically, is a mode for copying anunusable state due to an error. According to this mode A, for example,when the copy-target-path number is larger than the copy-source-pathnumber as shown in FIG. 10 (Aa), the states of all the copy-source pathsare respectively copied to the copy-target paths, and the state of thesurplus copy-target path is set to offline to coincide with the errorcopy-source path. Further, for example, when the copy-target-path numberis smaller than the copy-source-path number as shown in FIG. 10 (Ab),the surplus copy-source path, the state of which is not copied to thecopy target, is made an online copy-source path. If, for example, thenumber of offline copy-source paths is greater that the copy-target-pathnumber, the state of one copy-target path is set online, and the statesof the remainder of the copy-target paths are set to offline. Further,mode A is not limited to a copy that prioritizes offline like this, butrather can also carry out a copy that prioritizes online. Morespecifically, for example, the surplus copy-source path for which thestate is not copied to the copy target is set to an offline copy-sourcepath, and if, for example, the number of online copy-source paths isgreater than the copy-target-path number, the state of one copy-targetpath can be set to offline, and the states of the remainder of thecopy-target paths can be set to online.

Mode B is based on the copy-source-ON ratio. According to this mode B,for example, the states of the respective copy-target paths is decidedsuch that the copy-target-ON ratio constitutes the copy-source-ON ratio(for example, 4/4) as shown in FIG. 10 (Ba) (That is, in this example,all the copy-target paths are set online.). Further, as shown in FIG. 10(Bb), if it is not possible to make the copy-target-ON ratio the same asthe copy-source-ON ratio, the states of the respective copy-target pathsare decided such that the copy-target-ON ratio (for example 2/3) is asclose as possible to the copy-source-ON ratio (for example 2/4).Furthermore, in FIG. 10 (Bb), the copy-target-ON ratio is set to 2/3 inorder to prioritize online, but when prioritizing offline, thecopy-target-ON ratio can be set to 1/3. That is, in this mode B, thecopy-target-ON ratio can be made larger than the copy-source-ON ratio.Further, even if the number of online copy-target paths is larger orsmaller than the number of offline copy-target paths, as long as acopy-target-ON ratio that is as close as possible to the copy-source-ONratio can be obtained, it does not matter which copy-target-ON ratio isused. That is, a copy-target-ON ratio, which is obtained when online isprioritized and the number of online copy-target paths is larger thanthe number of offline copy-target paths, can be used, and conversely, acopy-target-ON ratio, which is obtained when offline is prioritized andthe number of online copy-target paths is smaller than the number ofoffline copy-target paths, can also be used.

FIG. 11 shows an example of the flow of processing carried out bycopy-target multi-path management software.

The copy-target multi-path management software determines whether or notthere is information in the failure information table 413 denoting afailure (S141).

If information denoting a failure is recorded (S141: YES), thecopy-target multi-path management software sends a copy-targetredundancy reply request to the integrated management computer 113(S142).

The copy-target multi-path management software, upon receiving thecopy-target redundancy information in response to this reply request(S143), writes the received copy-target redundancy information(information comprising the copy-target host volume identifier, thecopy-target-ON number and the copy-target-OFF number) to the path statustable 209S (S144). Consequently, the post-change (post-configuration)copy-source redundancy is reflected in the copy-target volume mapped tothe copy-source volume for which the status of the copy-source path hasbeen changed (configured).

The copy-target multi-path management software transitions to standbyfor a fixed period of time (S145), and thereafter executes S141.

The preceding is the flow of processing carried out by the copy-targetmulti-path management software. Furthermore, the copy-target multi-pathmanagement software, for example, can regularly send copy-targetredundancy reply requests to the integrated management computer 113regardless of whether or not a failure has occurred in the copy source.

FIG. 12 shows an example of the flow of processing carried out by thecopy-source storage management software 303S.

The copy-source storage management software 303S waits for post-changeinformation to be inputted from the user as information to be recordedin the CHA/VOL configuration table 311S and/or LUN securityconfiguration table 313S (S171).

The copy-source storage management software 303S, upon receiving theinputted post-change information (S172), writes the post-changeinformation to the CHA/VOL configuration table 311S and/or the LUNsecurity configuration table 313S (S173).

Subsequent to S173, the copy-source storage management software 303Swrites the post-change CHA/VOL configuration table 311S and/or LUNsecurity configuration table 313S to the integrated management computer113 (S104). Only the changed parts can be sent at this time.

Upon detecting a failure in the copy source (for example, a failure ofthe copy-source storage system 101S) (S175: YES), the copy-sourcestorage management software 303S notifies the integrated managementcomputer 113 of the occurrence of the failure (S176). The integratedmanagement computer 113, upon receiving this notification, writesinformation denoting the failure in the failure information table 413.

FIG. 13 shows an example of the flow of processing carried out bycopy-target storage management software.

The copy-target storage management software determines whether or notthere is information in the failure information table 413 denoting afailure (S181).

If information denoting a failure is recorded (S181: YES), thecopy-target storage management software sends a table reply request tothe integrated management computer 113 (S182).

If the copy-target storage management software receives informationrelated to the copy target recorded in the LUN security management table417 and/or CHA/VOL management table 419 in response to this replyrequest (S183), the copy-target storage management software writes thereceived information to the CHA/VOL table and/or LUN security table inthe copy-target storage system 101T (S184). Further, the copy-targetstorage management software writes the received information to thestorage CHA/VOL configuration table and/or LUN security configurationtable in the copy-target management computer 107T (S185).

The copy-target storage management software transitions to standby for afixed period of time (S186), and thereafter executes S181.

The preceding is the flow of processing carried out by the copy-targetstorage management software. Furthermore, the copy-target storagemanagement software, for example, can also regularly send table replyrequests to the integrated management computer 113 regardless of whetheror not there is a failure in the copy source.

The information written in S184 of FIG. 13 includes a set comprising acopy-target HBA port identifier and a copy-target CHA port identifierspecified by the copy-target LUN security change process.

The process that serves to start the copy-target LUN security changeprocess, and the copy-target LUN security change process will beexplained below.

LUN security information mapped to a certain copy-source CHA port can beadded, changed or deleted in the LUN security table 233S in thecopy-source storage system 101S. For example, this is carried out inaccordance with an indication from the copy-source management computer107S. Similarly, LUN security information can also be added, changed ordeleted in the LUN security configuration table 313S in the copy-sourcemanagement computer 107S in this case.

In this case, for example, the identifier of the above-mentioned certaincopy-source CHA port, either pre-change or deleted LUN securityinformation (hereinafter, copy-source pre-change security information),and either post-change added or deleted LUN security information(hereinafter, copy-source post-change security information) is sent fromthe copy-source storage management software 303S to the integratedmanagement computer 113 in S174 of FIG. 12. Furthermore, in the case ofan addition to the LUN security information, there is no copy-sourcepre-change security information.

For example, in S116 of FIG. 8, the integrated management software 403executes a copy-target LUN security change process. The condition forstarting the copy-target LUN security change process, for example, mayinclude the presence of copy-source post-update security information.More specifically, for example, when information denoting that there iscopy-source post-update security information configured in the LUNsecurity information in the post-update LUN security configuration table313, the copy-target LUN security change process starts.

The integrated management software 403 specifies the copy-target CHAport identifier mapped to the identifier of the above-mentioned certaincopy-source CHA port by referencing the CHA port mapping managementtable 411C (refer to FIG. 16B). The integrated management software 403also specifies the copy-target HBA port identifier, which is mapped tothe copy-source pre-update security information (hereinafter,copy-target pre-update LUN security information) and the copy-target HBAport identifier, which is mapped to the copy-source post-update securityinformation (hereinafter, copy-target post-update LUN securityinformation) by referencing the HBA port mapping management table 411B(Refer to FIG. 16A). The integrated management software 403 maps thecopy-target post-update LUN security information to the specifiedcopy-target CHA port identifier in the LUN security management table417. Further, if there is copy-target pre-update LUN securityinformation for the specified copy-target CHA port identifier in the LUNsecurity management table 417, the integrated management software 403deletes the copy-target pre-update LUN security information.

In S184 of FIG. 13, the post-update information recorded in the LUNsecurity management table 417, that is, the combination of thecopy-target CHA port identifier and the copy-target post-update LUNsecurity information is written to the LUN security table in thecopy-target storage system 101T. Further, the combination of thecopy-target CHA port identifier and copy-target pre-update LUN securityinformation is deleted from this LUN security table.

The addition, change or deletion of LUN security information in the copysource is reflected in the copy target by the above-described series ofsteps.

According to the above-described first embodiment, the integratedmanagement computer 113 has a host volume mapping management table 411Adenoting which copy-target host volume of which copy-target host ismapped to which copy-source host volume of which copy-source host. Whencopy-source redundancy is changed, copy-source redundancy informationdenoting the post-change copy-source redundancy for a certaincopy-source host volume is sent to the integrated management computer113. The integrated management computer 113 specifies a certaincopy-target host volume mapped to the above-mentioned certaincopy-source host volume by using the copy-source host volume identifiercomprised in this copy-source redundancy information to reference thehost volume mapping management table 411A. The integrated managementcomputer 113 decides the copy-target redundancy for the above-mentionedspecified certain copy-target host volume based on the above-mentionedcopy-source redundancy. Copy-target redundancy information denoting thedecided copy-target redundancy is sent from the integrated managementcomputer 113 to the copy-target host, which has the above-mentionedcertain copy-target host volume. This copy-target host configures thesent copy-target redundancy information for this certain copy-targethost volume in the copy-target redundancy. Consequently, the copy-sourceredundancy can be configured in the copy-target host without placing aburden on the user.

Embodiment 2

A second embodiment of the present invention will be explainedhereinbelow. The points of difference with the first embodiment willmainly be explained at this time, and explanations of the points sharedin common with the first embodiment will be simplified or omitted.

In the first embodiment, copy-target redundancy information is sent tothe integrated management computer 113 from the copy-source host 105S,and is sent from the integrated management computer 113 to thecopy-target host 105T. In the second embodiment, the route via which thecopy-target redundancy information is sent to the copy-target host 105Tdiffers. More specifically, the storage volume is utilized.

FIG. 14 shows the flow of the copy-target redundancy information untilit reaches the copy-target host 105T in a second embodiment of thepresent invention.

As shown by arrow 501, the integrated management computer 113(integrated management software 403) writes the copy-target redundancyinformation to the copy-source storage volume 133S mapped to thecopy-source host volume mapped to the changed copy-source redundancy.Both the copy-source storage volume 133S and the copy-target storagevolume 133T are partitioned into a data area, into which data from thehost operations software (hereinafter, user data) is written, and acontrol area, into which a type of data that differs from user data iswritten. The control area is capable of being accessed by the multi-pathmanagement software and the integrated management software 403, butincapable of being accessed by the operations software.

As shown by arrow 502, the copy-target redundancy information is writtento the control area of the copy-target storage volume 133T by a remotecopy between the copy-source storage volume 133S and the copy-targetstorage volume 133T.

As shown by arrow 503, the copy-target multi-path management software ofthe copy-target host 105T reads out the copy-target redundancyinformation from the control area of the copy-target storage volume133T. The copy-target multi-path management software updates the pathstatus table based on this read-out copy-target redundancy information.

The preceding is an explanation of the second embodiment.

Furthermore, the copy-target CHA port identifier, copy-target pre-updateLUN security information, and copy-target post-update LUN securityinformation can also be sent to the copy-target storage system 101Tusing an inter-volume remote copy. In this case, the CHA can read outthe copy-target CHA port identifier, copy-target pre-update LUN securityinformation, and copy-target post-update LUN security information fromthe copy-target storage volume, and can update the LUN security tablebased on this read-out information.

Further, the integrated management computer 113 (integrated managementsoftware 403) can also write the copy-target redundancy information tothe copy-target storage volume mapped to the copy-target redundancyinformation. The copy-target CHA port identifier, copy-target pre-updateLUN security information, and copy-target post-update LUN securityinformation can also be written to any of the copy-target storagevolumes from the integrated management computer 113.

Embodiment 3

FIG. 15 shows an example of the overall constitution of a system relatedto a third embodiment of the present invention.

There are a plurality of copy-source computer systems 111S for onecopy-target computer system 111T. In this case, for example, thecopy-target computer system 111T is logically divided into a pluralityof copy-target computer sub-systems as shown by the dotted line. Onecopy-target computer sub-system is mapped to one copy-source computersystem 111S. The respective copy-target computer sub-systems have atleast one copy-target host volume and at least one copy-target storagevolume.

The above-described embodiments of the present invention are example forexplaining the present invention, and do not purport to limit the scopeof the present invention solely to these embodiments. The presentinvention can be put into practice in a variety of other modes withoutdeparting from the gist thereof.

For example, the processing flow disclosed in at least one figure ofFIG. 7 through FIG. 9 and FIG. 11 through FIG. 13 shows an overview ofthe respective processes to the extent required to understand andimplement the present invention. Therefore, a so-called person havingordinary skill in the art will be able to change the order of the steps,and change a step to a different step without departing from the scopeof the present invention.

Furthermore, for example, a change in copy-source redundancy is notlimited to a manual operation by the user, but rather can also becarried out in accordance with other causes, for example, a change ofthe LUN security information in the copy target (for example, thedeletion of an online and/or offline copy-source path by deleting theidentifier of a certain copy-source HBA port (copy-source LUN securityinformation)).

1. A computer comprising: a first-path-redundancy acquisition unit foracquiring first-path-redundancy information, which is informationrelated to the redundancy of a first path linking a first storage volumeof a first storage system to a first host volume of a first host; aredundancy-configuration-destination specification unit for referencinghost volume mapping management information, which is informationdenoting which first host volume of which first host is mapped to whichsecond host volume of which second host, and for specifying the secondhost volume mapped to the first host volume connected to theredundancy-configured first path; a second-path-redundancy decision unitfor deciding the redundancy of a second path linking the specifiedsecond host volume to a second storage volume of a second storagesystem, based on the acquired first-path-redundancy information; and anoutput unit for outputting second-path-redundancy information, which isinformation related to the redundancy of the decided second path, sothat the decided second-path redundancy is configured in the second hosthaving the specified second host volume, wherein the first-pathredundancy is a value based on the number of active first paths, whichare active-state first paths of the plurality of first paths connectedto the same first host volume and the same first storage volume; thesecond-path redundancy is a value based on the number of active secondpaths, which are active-state second paths of the plurality of secondpaths connected to the same second host volume and the same secondstorage volume; the first storage system and one or more first hostsconfigure a first computer system; the first storage volume is a logicalvolume in the first storage system; the first host volume is a logicaldevice mapped to the first storage volume recognized by the first host;the second storage system and one or more second hosts configure asecond computer system; the second storage volume is a logical volume,which is in the second storage system, and which stores data that isstored in the first storage volume; and the second host volume is alogical device mapped to the second storage volume recognized by thesecond host.
 2. The computer according to claim 1, wherein, when thenumber of first paths for which redundancy has been configured and thenumber of second paths mapped to the redundancy-configured first pathsare the same, the second-path-redundancy decision unit decides aredundancy for the mapped second path that is the same redundancy as thefirst path redundancy.
 3. The computer according to claim 1, wherein,when the number of first paths for which redundancy has been configuredP_(s) and the number of second paths mapped to the redundancy-configuredfirst paths P_(t) are different, the second-path-redundancy decisionunit decides a redundancy, such that the percentage of the number ofactive second paths for the P_(t) is as close as possible to thepercentage of the number of active first paths for the P_(s) , as theredundancy for the mapped second path.
 4. The computer according toclaim 1, wherein, when the number of first paths for which redundancyhas been configured P_(s) and the number of second paths mapped to theredundancy-configured first paths P_(t) are different, thesecond-path-redundancy decision unit decides the redundancy of themapped second path based on the number of either active or passive firstpaths of the configured redundancy.
 5. The computer according to claim1, wherein, when P_(s)<P_(t) due to an error having occurred in any ofthe first paths, the second-path-redundancy decision unit decides theredundancy of the mapped second path such that the number of secondpaths in the passive state equals the number of error first paths, whichare first paths in which errors have occurred.
 6. The computer accordingto claim 1, wherein, when P_(s)>P_(t) due to an error having occurred inany of the second paths, the second-path-redundancy decision unitdecides the redundancy of the mapped second path such that the number ofpassive second paths, which are second paths in the passive state, is asclose as possible to the number of passive first paths, which are firstpaths in the passive state, by allocating an active first path for anerror second path, which is a second path in which an error hasoccurred.
 7. The computer according to claim 1, wherein the output unitwrites the second-path-redundancy information to the first storagevolume mapped to the first host volume to which theredundancy-configured first paths are connected.
 8. The computeraccording to claim 1, wherein the first storage system has a pluralityof first storage ports and a first access controller, the first storageport is a communication port for receiving an access command from afirst host, the first access controller is a first storage port to whichhas been mapped a first identification information mapped to a firsthost port, which is either the first host or a communication portthereof, and when an access command is received, the first accesscontroller allows this access command access if this access command isfrom either the first host or the first host port mapped to the firstidentification information; the second storage system has a plurality ofsecond storage ports and a second access controller, the second storageport is a communication port for receiving an access command from asecond host, the second access controller is a second storage port towhich has been mapped a second identification information mapped to asecond host port, which is either the second host or a communicationport thereof, and when an access command is received, the second accesscontroller allows this access command access if this access command isfrom either the second host or the second host port mapped to the secondidentification information, the computer further comprising: afirst-security-information acquisition unit for acquiring first securityinformation, which is information related to what first identificationinformation is mapped to which first storage port; an identificationinformation/storage port specification unit for referencingidentification mapping management information, which is informationdenoting which first identification information is mapped to whichsecond identification information, and storage port mapping managementinformation, which is information denoting which first storage port ismapped to which second storage port, and for specifying the secondidentification information mapped to the first identificationinformation specified from the first security information, and thesecond storage port mapped to the first storage port specified from thefirst security information; and a second-security-information outputunit for outputting second security information, which is informationrelated to the specified second storage port and the specified secondidentification information, such that the specified secondidentification information is mapped to the specified second storageport.
 9. The computer according to claim 8, wherein the first securityinformation is information related to which first identificationinformation mapped to which first storage port will change to what firstidentification information, the identification information/storage portspecification unit specifies the pre-change second identificationinformation mapped to the pre-change first identification informationspecified from the first security information, and the post-changesecond identification information mapped to the post-change firstidentification information specified from the first securityinformation, and the second security information comprises the specifiedpre-change second identification information and post-change secondidentification information.
 10. The computer according to claim 8,wherein the acquired first-path-redundancy information is informationrelated to the post-change redundancy of the first path through thefirst storage port, which changed as a result of the firstidentification information being mapped to the first storage port.
 11. Apath redundancy configuration method, comprising the steps of: acquiringfirst-path-redundancy information, which is information related to theredundancy of a first path linking a first storage volume of a firststorage system to a first host volume of a first host; referencing hostvolume mapping management information, which is information denotingwhich first host volume of which first host is mapped to which secondhost volume of which second host, and for specifying the second hostvolume mapped to the first host volume connected to theredundancy-configured first path; deciding the redundancy of a secondpath linking the specified second host volume to a second storage volumeof a second storage system, based on the acquired first-path-redundancyinformation; and outputting second-path-redundancy information, which isinformation related to the redundancy of the decided second path, sothat the decided second-path redundancy is configured in the second hosthaving the specified second host volume, wherein first-path redundancyis a value based on the number of active first paths, which areactive-state first paths of the plurality of first paths connected tothe same first host volume and the same first storage volume;second-path redundancy is a value based on the number of active secondpaths, which are active-state second paths of the plurality of secondpaths connected to the same second host volume and the same secondstorage volume; the first storage system and one or more first hostsconfigure a first computer system; the first storage volume is a logicalvolume in the first storage system; the first host volume is a logicaldevice mapped to the first storage volume recognized by the first host;the second storage system and one or more second hosts configure asecond computer system; the second storage volume is a logical volume,which is in the second storage system, and which stores data that isstored in the first storage volume; and the second host volume is alogical device mapped to the second storage volume recognized by thesecond host.
 12. A computer program, comprising: a program code foracquiring first-path-redundancy information, which is informationrelated to the redundancy of a first path linking a first storage volumeof a first storage system to a first host volume of a first host; aprogram code for referencing host volume mapping management information,which is information denoting which first host volume of which firsthost is mapped to which second host volume of which second host, and forspecifying the second host volume mapped to the first host volumeconnected to the redundancy-configured first path; a program code fordeciding the redundancy of a second path linking the specified secondhost volume to a second storage volume of a second storage system, basedon the acquired first-path-redundancy information; and a program codefor outputting second-path-redundancy information, which is informationrelated to the redundancy of the decided second path, so that thedecided second-path redundancy is configured in the second host havingthe specified second host volume, wherein first-path redundancy is avalue based on the number of active first paths, which are active-statefirst paths of the plurality of first paths connected to the same firsthost volume and the same first storage volume; second-path redundancy isa value based on the number of active second paths, which areactive-state second paths of the plurality of second paths connected tothe same second host volume and the same second storage volume; thefirst storage system and one or more first hosts configure a firstcomputer system; the first storage volume is a logical volume in thefirst storage system; the first host volume is a logical device mappedto the first storage volume recognized by the first host; the secondstorage system and one or more second hosts configure a second computersystem; the second storage volume is a logical volume, which is in thesecond storage system, and which stores data that is stored in the firststorage volume; and the second host volume is a logical device mapped tothe second storage volume recognized by the second host.